Evaluation Based on Siemens Simatic PCS7 System
Any industry that has a requirement for a heated medium, whether it is used for process, utilities or emissions, utilizes equipment that has combustion controls and combustion safeguards.
There has been an evolution in these controls from a traditional control that separates the DCS from either a relay-based system, PLC or Safety PLC for combustion safeguarding, to combined control for systems with less complexity as in a single burner BMS.
Functional safety standards like IEC 61511 do permit combined control and combustion safeguarding in one system. Other standards like the 2015 edition of NFPA 85 now explicitly allow combining combustion control and combustion safety in the same logic solver for certain applications. However several design issues must be considered and properly addressed in order to maintain or improve safety performance.
A properly designed combination combustion control and combustion safeguarding system can enhance the Safety Lifecycle by reducing engineering, operations and maintenance errors and improve combustion safety.